Simple SSE middleware with implicit routing

index.js

var app = express();

var sse = new SSE();

app.get('/foo', function() {
  sse.emit('sse', { message: 'hello, sse !' });
});

app.use('/sse', sse.forward('sse')); // The param to forward is the name of the dispatched event

sse-middleware.js

var EventEmitter = require('events').EventEmitter;
var util = require('util');

function SSE() {
	EventEmitter.call(this);
}

util.inherits(SSE, EventEmitter);

SSE.prototype.forward = function(eventName) {
	var self = this;

	return function(req, res, next) {
		console.log('sse:open/' + eventName);

	  res.header('Content-Type', 'text/event-stream');
	  res.header('Cache-Control', 'no-cache');
	  res.header('Connection', 'keep-alive');

	  var id = 0;

	  self.on(eventName, onevent);

	  function onevent(data) {
	  	console.log(eventName, data);
	    res.write('id: ' + id + '\n');
	    res.write('data: ' + JSON.stringify(data) + '\n\n');
	    id++;
	  }

		req.socket.once('close', function() {
			self.removeListener(eventName, onevent);
			console.log('sse:close/' + eventName);
		});
	};
}

module.exports = SSE;